In manufacturing processes, transfer apparatus are used to create repeated mechanical motions for production equipment such as walking beams, pick and place movements, oscillating drives, and the like. These mechanical motions are carried out in a single plane and are characterized by requiring a high horizontal stroke to vertical stroke ratio.
Typically, the long horizontal stroke is accomplished by a large barrel cam or a large plate cam having linkages attached to the cam followers for driving the worktool along the repeating and recirculating path. When extremely long horizontal strokes are required, stroke doubling gear and belt mechanisms are frequently employed.
The prior art transfer apparatus are particularly deficient in that the conventional long stroke cam motions require large cam sizes and long length linkages and levers to drive the worktool. The large cams have inherently high inertia requiring high torque inputs. The long linkages and levers tend to magnify any errors occurring in the manufacture of the lever or linkages, and errors due to wear.